Massachusetts Congressmen who want Sen. John Kerry’s (D) seat if he wins the presidency downplayed their activity level but clearly are preparing for a special election, should one be held.

“A lot of what you do to run for the Senate, you do anyway in my line of work,” Rep. Barney Frank (D) said. “You raise money. I’m raising money anyway.” A spokesman for Rep. Stephen Lynch (D) said his boss is proceeding similarly.

“He’s certainly running for Congress” again, Matt Ferraguto said. “He’s reaching out to supporters anyway.”

Likewise, Lynch volunteers have been helping him collect signatures to put him on the primary ballot this year — a formality required by Massachusetts law — and could readily be mobilized for a Senate run if and when the time comes, he said.

Ferraguto denied that Lynch was lining up support and money specifically with an eye toward the Senate.

“Everybody views it as purely speculative right now,” he said. Any discussions about a Senate bid have not moved past Lynch’s immediate family, Ferraguto said.

Rep. Marty Meehan (D) also dismissed the notion that he was getting his Senate ducks in a row.

“It’s a hypothetical question; we really need to get John Kerry elected [president] first,” he said.

As for rumors that he’s raising Senate campaign cash, Meehan said: “I’m raising money for my House race.” He noted that two Republicans are vying for the right to challenge him and that the GOP is “always working my district.”

Frank, who has made it known he would be interested in an open Senate seat, said, “I’m not asking people for commitments at this point. It would be a mistake to start an all-out campaign [now and] it wouldn’t be fair to Kerry.”

Frank, Lynch and Meehan are the Massachusetts House Members mentioned most prominently as likely to try to succeed Kerry if he becomes president. But speculation has also centered on Reps. Ed Markey, John Tierney and Bill Delahunt, who are all Democrats.

Former Rep. Joe Kennedy (D) is also considered a possible Senate candidate.

Of course, a lot of pieces have to fall into place to make relevant any speculation about who would run and who would not.

First, the Massachusetts Legislature would have to change the rules. Under current law, if Kerry vacates his seat Gov. Mitt Romney (R) would appoint someone to serve out the next two years of Kerry’s Senate term. A special election would then be held coinciding with the 2006 general election to fill the final two years of Kerry’s term.

Democrats, who control the state Legislature, have already introduced legislation replacing that gubernatorial prerogative with a quick special election.

They anticipate having enough votes to override a Romney veto.

Finally, Kerry would have to ascend to the presidency — an outcome that is far from certain.

But if the bill becomes law and if Kerry moves on to the White House, a special election to replace him would likely be held in spring 2005.

Despite the protestations of the would-be candidates, Michael Goldman, a Bay State Democratic consultant, said contenders must be, at least quietly, laying the groundwork.

“If they’re not raising money, they should be,” Goldman said.

“It’s never unseemly to raise money, but it is to look for a job that’s not available yet,” he said, explaining the delicate balance the Congressmen must maintain. “There’s no reason to get ahead of the parade here.”

Even so, “it’s a once-in-a-lifetime opportunity,” Goldman said, noting that the last time a Senate seat became available in Massachusetts was in 1984, when Kerry was elected to replace Paul Tsongas (D), who stunned the political world by announcing that he would not seek a second term.

Sen. Edward Kennedy (D), who won a special election in 1962 to fill the remainder of his brother John F. Kennedy’s Senate term after JFK was elected president, said Sunday on NBC’s “Meet the Press” that he plans to seek another term in 2006.

That might explain why Lynch, who has served in the House since only 2001, is already contemplating moving up to the Senate if there is a vacancy.

“It’s so rare, a lot of candidates view it as a unique chance,” Ferraguto, the Lynch spokesman, said.

A number of Lynch’s seniors in the delegation might also be interested.

Markey, who has served in the House since 1976, “will seriously consider an open Massachusetts Senate seat when John Kerry wins the presidency in November,” Markey spokesman Israel Klein said.

Meehan said “I certainly wouldn’t rule it out” when asked if he would run.

Frank, who has been perhaps the most public about his interest, said his ambition comes with many asterisks.

If Democrats win back the House, or come within striking distance for 2006, Frank said he will not run, even if Kerry wins the presidency and Bay State Democrats approve a special election.

Frank is in line to become chairman of the powerful Financial Services Committee if Democrats take control of the House.

Likewise, if Romney retains his appointment power, Frank would not run.

If a referendum to ban gay marriage in Massachusetts gets slated for the 2006 ballot, Frank still would not run, as he would want to work against such an initiative, which, he acknowledged, could hurt his Senate chances.

So in fact, Frank will run only if the election law gets changed, Kerry wins, Democrats do not take back the House and the gay marriage issue is not on the 2006 ballot.

A poll conducted on behalf of the Boston Herald in late February found that Bay State voters favor a special election and want Joe Kennedy to replace Kerry.

Kennedy got 25 percent of polled voters, while Romney received 14 percent and Meehan 10 percent.

Meehan was the only Congressman tested in that poll.

Romney has said he would not appoint himself to the seat if he retains the power to do so, though he is almost certain to name a Republican.

Goldman said there is no indication that Joe Kennedy, who served in Congress from 1986 to 1998, wants back into public life.

All the Democrats mentioned “come to the table with strengths,” Goldman said.

Frank, for example, has represented different parts of the state as his district has changed over the years and is a “fierce debater,” Goldman said.

And he does well among his more conservative South Shore voters, he said.

Meanwhile, Meehan’s name has been out there for a long time and he is an excellent fundraiser, Goldman said.

Three of the most discussed would-be contenders can also play to their different bases, Goldman said.

Among voters, Frank is seen as representing the liberal wing, Meehan is believed to be the more moderate Democrat and Lynch comes across as a more conservative Democrat, he said.

All the talk about “promotion” within the delegation is not likely to cause problems among the 10 House Members, all of whom are Democrats, Goldman said.

“It’s the business of politics, of moving up,” he said. “I don’t feel they would snipe at each other.”

Frank agreed.

“[There’s] no negative impact at all. We’ve been around, nobody feels angry at anyone else, no one feels like ‘this is mine and you’re taking away from someone else,’” he said.